Okay, I'll solve this problem right now: Specialist Gear.
You know how Shepard can buy amour pieces at stores, customize them, and STILL never look like any other character in the game? That's because Shepard always wears specialist gear!
If EVERY character in ME3's main cast could by (and unlock) Specialist gear, then you get rid of several problems that people seem to have:
1) Credits can be spent at stores. There will be sections within the kiosks for each race, human, Turian, Asari, etc, and each section will have it's own specialist gear. This will get rid of the annoying problem of having massive amounts of money, with no place to spend it.
2) Unique look. Specialist armor will never look the same. Turian Special Shocktrooper Armor (TSSA) will never look the same as human Shocktrooper Armor. Garrus will fill it out to his own requirements. You can of course paint it/design it if you want, but you'll never have to as a default, as its default will have it's own design to go with Garrus specifically. N7 Armor (the kind Shepard wears) will never look the same as Alliance Top Secret Armor (which Ash will wear), as a default.
Also, one could buy casual wear for each character. There would be three kinds:
1) military casual -- a SR2 uniform
2) cultural uniform -- an Asari would wear Asari specific fashion, a Drell would wear Drell specific fashion, etc
3) formal wear -- everyone would get their own style of formal wear
3) Stats. Each armor type will have very clear and very precise stats so that you guys with a short attention span can easily see the pros to each set. Heavy armor adds 25% shields. Medium armor subtracts 25% recharge time. Light armor adds 25% motion speed. Simple. You would always know that Armor X and Y have the same bonuses, but X might look better to you.
And of course, every class will get it's own unique, purely aesthetic value pieces as well. Shoulder pads, helmets, gauntlets, ammo packs (which might raise the NPCs fire power a bit), belts, etc, etc. Little things that make the default uniqueness even more unique.
So, to wrap up, it would be similar to going into a store, and buying Alt. Packs for every character, with mostly visual appeal, but also clear cut advantages. This gets rid of money hoarding, gets rid of spending hours looking for which set has the best stats.